<template>
<div class="todo-footer" v-show="total">
  <label>
    <!-- <input type="checkbox" :checked="isAll" @change="checkAll"/> -->
    <input type="checkbox" v-model="isAll"/>
  </label>
  <span>
    <span>已完成{{doneTotal}}</span> / 全部{{total}}
  </span>
  <button class="btn btn-danger" @click="clearAll">清除已完成任务</button>
</div>
</template>

<script>
export default {
  name: 'MyFooter',
  props: ['todos','checkAllTodo','clearAllTodo'],
  computed: {
    //总数
    total(){
      return this.todos.length
    },
    //已完成数
    doneTotal(){
      //此处使用reduce方法做条件统计
      /* const x = this.todos.reduce((pre,current)=>{
        console.log('@',pre,current)
        return pre + (current.done ? 1 : 0)
      },0) */
      //简写
      return this.todos.reduce((pre,todo)=> pre + (todo.done ? 1 : 0) ,0)
    },
    //控制全选框
    isAll:{
      //全选框是否勾选
      get(){
        return this.doneTotal === this.total && this.total > 0
      },
      //isAll被修改时set被调用
      set(value){
        this.checkAllTodo(value)
      }
    }
  },
  methods: {
    /* checkAll(e){
      this.checkAllTodo(e.target.checked)
    } */
    //清空所有已完成
    clearAll(){
      this.clearAllTodo()
    }
  },
  data(){
		return {

		}
  }
}
</script>

<!-- Add "scoped" attribute to limit CSS to this component only -->
<style scoped>
/*footer*/
.todo-footer {
  height: 40px;
  line-height: 40px;
  padding-left: 6px;
  margin-top: 5px;
}

.todo-footer label {
  display: inline-block;
  margin-right: 20px;
  cursor: pointer;
}

.todo-footer label input {
  position: relative;
  top: -1px;
  vertical-align: middle;
  margin-right: 5px;
}

.todo-footer button {
  float: right;
  margin-top: 5px;
}
</style>
